The Vonage Client SDK for Android, iOS, and Web was released last year, initially with In-app Voice and later with In-app Messaging capabilities. A transition guide is available to help developers switch from the previous version of the SDK, covering changes to client instantiation and session management, as well as new features like muting and hanging up. For more information and support, developers can refer to the Vonage Client SDK documentation or tutorials, and reach out to the Vonage Community Slack or [email protected] for assistance.